Numerical Modeling of Hydraulic Transients in a Failure Water Supply Pumping Pipeline System Due to Power Outage: Nasiriyah Water Supply Project, Iraq

This paper employed a hydraulic model to investigate the transient flow and its hydrodynamic effects in a failed water supply pumping pipeline system during a sudden and unplanned power outage.The model was developed and then properly calibrated to make the system more efficient in locating and determining the change in pressure and discharge throughout the length of the pipeline.The simulation of the transient process was utilized using the method of characteristics.The model was conducted on a practical problem in a hydraulic system of pipelines and pumping station of a water supply-pumping station, which is possessed by Nasiriyah Water Supply Project No.1 The Giant Nasiriyah Water Project (GNWP), Thi-Qar, Iraq, where the power outage is the most common and unsolved problem.The project transmits water for more than 77 km to supply more than 800 thousand inhabitants in the dry areas in southern Iraq with drinking water.The pressure variation and flowrate change at different points for the system with the different timings shutting down were analyzed.The study results showed that the sudden shutdown of the pump generates fluid transients with highpressure variations and flowrate in different locations and times.The characteristics of pumping under the transient conditions showed high fluctuations during the movement between the pump shut-off point and mass flow points, and the magnitudes of the fluctuations decreased with the fading of the impact of the water hammer.The results also indicated that the studied system is experiencing high-pressure pulsations in the discharge of the pumping system in addition to negative pressures, and consequently threatening problems of collapses and severe cavitations are expected along the pipeline in the system.This study may help to prevent the pipeline pumping system from hazards due to transient pressure fluctuations using the most principal recommendations for engineering solutions.